This invention relates to a blade of a row of rotor blades or stator blades for use in a turbomachine.
The flow in blade rows of aerodynamically highly loaded turbomachines is characterized by a very high flow deflection that has to be achieved. The necessary flow deflection can be, either in parts of the blade height or along the entire blade height, so high that a conventional blade profile section shape, designed according to the state of the art, leads to premature separation of the boundary layer flow on the blade profile and in the side wall area on hub and casing. Conventional blades, as shown in FIGS. 12A, 12B, without additional design features for stabilization of the profile and wall boundary layers, are unsuitable on account of extremely high pressure losses and non-achievement of the required flow deflection. In addition, the secondary flows occurring in the area of the confining side walls (on hub and casing) become uncontrollable and lead to further very high total pressure losses. The consequence of this is overall poor performance characteristics of the turbomachine.
Blades with a design according to the state of the art, see FIGS. 12A, 12B, have, on account of the heavy aerodynamic loading occurring in the boundary layers, i.e. the two-dimensional boundary layers on the profile and the three-dimensional boundary layers on the hub and casing wall, too low a working range and too high losses for delivery of the operating characteristics required in modern turbomachines.